Blockade and reversal of 5-methoxy-N,N-dimethyltryptamine-induced analgesia following noradrenaline depletion.

Abstract

The acute effects of the 5-hydroxytryptamine agonist, 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT), upon pain sensitivity, using shock titration, tail-flick and hot-plate methods, in noradrenaline- and 5-hydroxytryptamine-depleted rats were examined. Noradrenaline depletion, following the systemic administration of N-2-chloroethyl-N-ethyl-2-bromobenzylamine hydrochloride (DSP4, 2 X 50 mg/kg, i.p.), caused a reversal of the analgesic effect of 5-MeO-DMT on shock-titration from hypo- to hypersensitivity, and a total blockade of the antinociceptive effect of 5-MeO-DMT upon pain responses in the hot-plate and tail-flick tests. Pretreatment with either p-chloroamphetamine (2 X 10 mg/kg) or p-chlorophenylalanine (200, 100, 100 mg/kg), that depletes central 5-hydroxytryptamine stores, failed to alter the analgesia caused by acute 5-MeO-DMT. Strong evidence is provided for the effect of central noradrenaline depletion upon the analgesic effect of the 5-HT agonist. These findings suggest an important tonic influence of the noradrenaline system upon the descending spinal 5-HT pathway in rats.

• Authors: T Archer, B G Minor, C Post
• Journal: Brain research (Brain Res) Vol. 333 Issue 1 Pg. 55-61 (Apr 29 1985) ISSN: 0006-8993 [Print] Netherlands
• PMID: 3158373 (Publication Type: Journal Article)

Chemical References

• Analgesics
• Benzylamines
• Methoxydimethyltryptamines
• Serotonin
• p-Chloroamphetamine
• DSP 4
• Fenclonine
• Norepinephrine

Topics

• Analgesics (pharmacology)
• Animals
• Benzylamines (pharmacology)
• Central Nervous System (drug effects)
• Drug Interactions
• Fenclonine (pharmacology)
• Male
• Methoxydimethyltryptamines (pharmacology)
• Norepinephrine (physiology)
• Rats
• Rats, Inbred Strains
• Serotonin (analogs & derivatives, physiology)
• p-Chloroamphetamine (pharmacology)